Inhibitory Effect of Acetaminophen on Ocular Pigmentation and its Relationship with Thyroxine in Zebrafish Embryos.

Acetaminophen (N-acetyl-p-aminophenol; APAP) is one of the most widely used analgesics. To examine the toxicity of APAP, we used zebrafish embryos as model animals to detect the effect of APAP on the thyroid system of zebrafish embryos. The zebrafish embryos were exposed to APAP from 4 h post fertilization (4 hpf) until observation. The experimental results showed that APAP caused pericardial edema and decreased pigmentation in the zebrafish embryos or larvae. The APAP treatment caused a decrease in the expression of tpo and thrβ in the zebrafish at 36 and 72 hpf. The transcriptomic analysis found that APAP affected retinol metabolism, the metabolism of xenobiotics by cytochrome P450, and the tyrosine metabolism pathway. The harmful effect of APAP on zebrafish embryos might be due to its disrupting effect on the functional regulation of the thyroid hormone system.